This invention relates generally to valve actuating methods and apparatus and, more particularly, to booster pilot valves.
In recent years, industrial facilities, such as pharmaceutical or petrochemical plants, employ low-energy Bus systems to operate and control various processes. The low-energy Bus systems operate with currents ranging from 1.5 to 10 mA at an input voltage of 6 to 30 volts. The low-energy Bus systems consume less power than previously used operating and control systems. The use of low-energy Bus systems may reduce the overall operating expenses of the plants, among other advantages.
With the introduction of low-energy Bus systems has also come a demand for valves that operate with the limited power supply of the Bus system. Large valves typically require a considerable amount of power to open and close, more power than may be available through the low-energy Bus system. Consequently, it has become a common practice to mount an air-powered cylinder on or near a large valve to actuate it. The air cylinder is often actuated by a solenoid or a pilot valve that is in communication with the air cylinder. The pilot valve requires much less power than conventional valve actuators. Therefore, it is desirable to design a pilot valve that operates at the extremely low power levels of low-energy Bus systems to actuate a larger valve. In addition, it is desirable that the pilot valve be compatible with a particular Bus system being used in a plant.
The present invention is directed to providing a booster pilot valve operating at very low power levels to actuate a larger valve.
In accordance with one aspect of the present invention, a booster pilot valve includes a body and a hydraulic member. The body defines a fluid chamber. The hydraulic member is disposed in the fluid chamber and is movable by a pressurized flow between a first and a second position. The hydraulic member in the first position permits a cylinder port to communicate with a first ancillary port. The hydraulic member in the second position permits the pressurized flow to communicate with the cylinder port. In a further embodiment, the booster pilot valve includes a secondary device operable to direct the pressurized flow.
In accordance with another aspect of the present invention, a booster pilot valve includes a body and a spool. The body defines a fluid chamber having a main port and an outlet port. The spool is disposed within the fluid chamber and is movable by a pressurized flow between a closed position and an opened position. The spool in the closed position permits a secondary flow form a cylinder port to communicate with a first ancillary port. The spool in the opened position permits the pressurized flow from the main port to communication with the cylinder port. In a further embodiment, the booster pilot valve includes a secondary valve communicating with the outlet port of the body. The secondary valve is operable to direct the pressurized flow entering the main port to move the spool to the closed or opened position. The secondary valve may include a three-way valve or may include a piezotronic valve.
In accordance with yet another aspect of the present invention, a booster pilot valve includes a body and a hydraulic member. The body defines a fluid chamber and includes a main port and a stem. The main port is defined in a first end of the fluid chamber, and the stem protrudes into the fluid chamber from a second end. The stem defines an outlet port aligned with the main port. The hydraulic member is disposed in the fluid chamber and is movable between opened and closed positions within the fluid chamber. The hydraulic member includes first and second surfaces and a fluid passageway. The first surface is adjacent to the first end of the fluid chamber. The second surface is adjacent to the second end of the fluid chamber. The fluid passageway is defined in the hydraulic member and extends from the first surface to the second surface. The stem is partially disposed within the fluid passageway so that the fluid passageway communicates the main port with the outlet port. The hydraulic member in the opened position permits fluid communication of the main port with a cylinder port. The hydraulic member in the closed position permits fluid communication between the cylinder port and a first ancillary port.
In accordance with a further aspect of the present invention, a method of operating a valve element with a hydraulic device includes: supplying a pressurized flow into the hydraulic device; directing the pressurized flow to the valve element by selectively concentrating the pressurized flow to move the hydraulic device to an opened position; and directing a secondary flow from the valve element to an ancillary port in the hydraulic device by selectively concentrating the pressurized flow to move the hydraulic device to a closed position.
The foregoing summary is not intended to summarize each potential embodiment, or every aspect of the invention disclosed herein, but merely to summarize the appended claims.